Fuel additives are used today to improve the performance of gasoline and diesel fuels either because the hydrocarbon components themselves contain some deficiency or adding a small amount of an additive is more effective than changing the composition of these fuels. The primary thrust of research and development in the field of fuel additives has been towards attempting to provide fuels which contain deposit control additives. Effectively controlling or inhibiting deposit formations in the intake system, such as carburetor, valves, etc., of internal combustion engines can improve fuel efficiency. However, this must be accomplished without contributing to combustion chamber deposits which can produce harmful exhaust emissions with subsequent damage to catalytic converters and the environment.
Deposits in the combustion chamber of an internal combustion engine can contribute to an increase in smoke and exhaust emissions. Smoke originates principally from two sources within the engine: first, unburned or partly oxidized fuel, and second, unburned carbon that has been formed by thermal decomposition of the fuel that has not reacted with oxygen. Thus, a chemically correct and uniform mixture of fuel and air is necessary at the instant of ignition for fuel efficiency. However, this can only be accomplished if fuel and carbon deposits are prevented from inhibiting the flow of air and fuel into the combustion chamber.
In addition to unwanted deposits in an engine, inclusion of water in hydrocarbon-base fuels may reduce fuel oxidation and cause a blockage in the fuel system. Water may be present from moisture condensing out of hot fuel as it cools in storage tanks or pipelines. Also, acidic or caustic water may be carried over inadvertently from various processes in the refinery. Corrosion-causing free water in the fuel system of a vehicle can lead to severe problems. Not only can leaks develop in automobile fuel tanks, but particles of rust can block fuel lines, filters, fuel injection nozzles and critical carburetor orifices, such as jets. Moreover, water in fuel can prevent ignition and/or complete oxidation of the fuel. As a result, there is an increased need for adding corrosion inhibitors to hydrocarbon-base fuels.
Accordingly, improved fuel additive compositions are needed that inhibit corrosion in the fuel system, reduce incomplete combustion deposits, reduce exhaust emissions, and increase fuel combustion and efficiency.